macro's out-compete other nuisance algaes, so if you plant them in a fuge, you'll minimize the unwanted algae in the display tank. With that said, it's important to choose your macro wisely. They are usually attractive algaes, but some can get out of control and take over your main tank quite quickly.
I have grape caulerpa in my fuge, and keep it trimmed regularly. The tank I got it from was competely overgrowm in it.... a huge task to rid it. It's said that if you keep lighting it 24/7, then it won't go sexual and spread like that. I haven't had any problems yet, but the tank is still young.
Chaetomorpha is probably your best bet. It won't go sexual, and is fairly aggressive at nutrient removal... plus it's not nearly as noxious as the caulerpa's.